Microhabitat requirements of the great crested newt (<i>Triturus cristatus</i>) in a woodland area

The great crested newt Triturus cristatus is one of Europe's fastest declining amphibian species. This thesis aimed to increase our knowledge of the microhabitat use and ecology of great crested newts within a woodland area in the British Isles and suggest ways of improving measures for conservation. The study was conducted at Epping Forest Field Centre and surrounding deciduous woodland at High Beach, Epping Forest, which is situated to the north-east of London. Capture-mark-recapture of adults in four ponds over 5 years within a 1 km area revealed that great crested newts exhibited large fluctuations in detection probabilities, highlighting the importance of calculating detection before making inferences of population size or survival. Apparent annual survival was constant between ponds and years; male survival was 0.40 compared to 0.58 in females. Only 11 inter-pond movements were recorded. Many terrestrial juveniles occupied cover objects close to breeding ponds for many months of each year. Growth rates were fastest in smallest individuals (35.to 39 mm SVL) and juvenile body condition varied through each year. Juveniles had high monthly survival (0.56 to 0.77) and a low constant apparent annual survival of 0.19. Adult males exhibited lowest body condition index (BCI) in March and June while females had high BCI in March and lowest in April. Larger males with a higher body condition were more likely to possess taller crests. Experiments showed increased mortality in great crested newt embryos when raised in the presence of caged predatory sticklebacks compared to controls. Great crested newt larvae utilised vegetated microhabitats for a significantly greater proportion of the time when in the presence of caged predatory sticklebacks but not when faced with non-predatory crucian carp. Finally, great crested newt females exhibited a non-random distribution in egg laying. Individuals preferred to lay eggs on clean compared to occupied strips. These findings are discussed in relation to improving our understanding of great crested newt ecology and conservation.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

The Open University

Year dc:date.issued

2012

Author dc:creator

• Jarvis, Laurence Edward

Language dc:language

en